Light guiding via refraction was first demonstrated in the 1840's. One seminal experiment demonstrated that light directed into a parabolic stream of water is totally reflected by the water's surface. Thus, light entering the stream of water does not exit the stream of water, and instead remains culminated in the stream even when the stream bends.
These early experiments gave rise to our understanding of total internal reflection. When light traveling in a dielectric hits a boundary at an angle (larger than the critical angle) the light is totally reflected. This effect is used in many optical devices today, and governs many communications technologies.
One implementation of light guides/total internal reflection is the optical fiber. An optical fiber generally is a transparent, flexible fiber made by extruding glass or plastic. Optical fibers are often used to transmit light between the two ends of the fiber. This is applicable in the field of optical communications, where optical fibers allow for higher bandwidth transmissions over longer distances than conventional wire cables. Fibers are used in lieu of metal wires because fibers suffer less loss: electron flow in metal wires may be disrupted by scattering events in the metal lattice and/or electromagnetic interference from external sources.